N-vinyllactam derivatives and polymer thereof

ABSTRACT

N-vinyllactam derivatives protected at the 3-position are provided and represented by the following formula (I). These are polymerized into homo- and copolymers for use in microlithography of semiconductor manufacture. The polymers are used as a photoresist material suitable for a deep UV process so that pictures of high sensitivity and high resolution can be obtained. In addition, ultrafine circuits can be formed and an exceptional improvement in pattern formation can be accomplished through the use of the photoresist of the invention.

This application is a Divisional of U.S. patent application Ser. No.08/713,085, filed Sep. 12, 1996.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel N-vinyllactam derivatives andpolymers thereof for use in microlithography. More particularly, thepresent invention relates to N-vinyllactam derivatives and polymersthereof, used as materials for photoresist which is capable of formingpicture of high sensitivity and high resolution by use of deep UV and tohomo- and copolymers thereof for use as photoresist.

2. Description of the Prior Art

Usually, photoresist consists mainly of an alkali-soluble phenol-(orcresol-)formaldehyde novolak resin and a substituted naphthoquinonediazide compound as a photosensitive material (photoactive ingredient),as described in U.S. Pat. Nos. 3,666,473, 4,115,128 and 4,173,470.

While the novolak resin used in such photoresist is dissolved in anaqueous alkali solution, the naphthoquinone photosensitive material actsas a dissolution inhibitor of resist. However, when a substrate coatedwith the photoresist is selectively subjected to chemical radiation, thephotosensitive agent is induced to suffer from such structuralmodification that the exposed region of the photoresist coating is ofstronger solubility to alkali than the unexposed region. By virtue ofsuch differences in solubility, a relief pattern can be carved on thecoating of the substrate. That is, when the substrate is immersed in analkaline developing solution, the exposed region of the photoresistcoating is dissolved whereas the unexposed region is not substantiallyaffected, forming a pattern. However, the above-mentioned novolak typeresists were not found to be suitable to the steper utilizing shorterwavelength, which will be used in the future, because they show highoptical absorbance in the range of deep ultraviolet light, 200 to 300nm.

In order to accomplish high sensitivity in the lithography process ofsemiconductor manufacture, chemical amplification resist has recentlybeen developed. Indeed, the chemical amplification resist has been inthe limelight since it was found to have the capacity for increasingsensitivity 100-fold over conventional positive novolak resists.Chemical amplification resist, which takes advantage of the photoacidgenerator (hereinafter referred to as "PAG"), is generally prepared byformulating PAG in a matrix polymer of a structure sensitively reactingto acid. For the mechanism of the photoreaction, when PAG is exposed tolight or irradiated by a high energy beam, such as X-ray and electronbeam, strong protonic acid, Bronsted acid, are generated, causing themain chain or the side chain of the matrix polymer to react towarddecomposition, crosslinking or large change in polarity. This action ofthe acid induces, at the irradiated region, the solubility of the givendeveloping solution to be altered. That is, increased or decreased. As aresult, fine patterns can be formed.

Onium salt which is able to respond to light and radiation is known asthe photoacid generator. Onium Salt typically includes ammonium salts,oxonium salts and sulfonium salts, etc. Recently, it has been reportedthat organic sulfonic ester can function as the photoacid generated.

Available for the matrix polymer, which can react with acid, is forexample, polymers having a side chain such as t-butylester,t-butylcarbonate, t-butoxy or t-butoxycarbonyl groups, which can bedecomposed into carboxylic acid, phenol or alcoholic functional group byacid. Among such side chain protecting groups, the t-butoxycarbonylgroup is highest in sensitivity. Such acid-reactable polymer in aprotected state or prior to reaction with acid, can be dissolved in anorganic solvent but insoluble in an alkali aqueous solution. However, ifthe acid-reactable polymer is deprotected by reaction with acid, it issoluble in alkali aqueous solution because its polarity is significantlychanged.

Using this principle, the development of chemical amplification resistshas been a hot issue in recent years. T-Butoxycarbonyl-protectedpolyvinylphenol (hereinafter referred to as "t-bocPVP") is reported tobe one of the most promising resins, as introduced in U.S. Pat. Nos.4,491,628, 4,405,708 and 4,311,782.

A recent trend in submicrolithography is to use as a light source deepuv (wavelength 200 to 300 nm), preferably, a KrF excimer laser of highpower (wavelength 248), rather than conventional uv, e.g. g-line(wavelength 436 nm) or i-line (wavelength 365 nm), in order toaccomplish high sensitivity and high resolution. Therefore, the opticalabsorption of the matrix polymer should be minimized in the wavelengthrange of deep uv, particularly at 248 nm, the wavelength of KrF excimerlaser. However, since t-bocPVP also contains the benzene group, it hasthe significant disadvantage of showing large optical absorption inshort wavelength ranges.

SUMMARY OF THE INVENTION

Intensive research repeated by the present inventors aiming to develop aphotoresist for submicrolithography which does not absorb deep uv inaddition to having a high glass transition temperature necessary forprocessing procedure resulted in the finding that the chemicalamplification resist polymerized with an alicyclic compound(N-vinyllactam) protected by an acid-reactable group is converted intoan aqueous polymer when being deprotected and can thus be designed toform a pattern by using a weak alkali aqueous solution or pure wateronly, instead of strong alkali aqueous solution, thereby improving thepattern-forming processes considerably.

Therefore, it is a principal object of the present invention to providean N-vinyllactam derivative monomer in which vinyllactam is blocked atthe 3-position by various kinds of protecting groups, as a photoresistmaterial for microlithography which satisfies high sensitivity and highresolution.

It is another object of the present invention to provide a polymerprepared from the monomer.

It is a further object of the present invention to provide a polymer foruse in photoresist.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a vinyllactam derivative monomer in whichvinyllactam is protected at its 3-position. The monomer can be preparedby reacting vinyllactam with a strong base at low temperatures to givean enolate and introducing a protecting group into the 3-position ofvinyllactam. Concrete examples of vinyllactam includeN-vinylpyrrolidone, N-vinyl-4-butylpyrrolidone,N-vinyl-4-propylpyrrolidone, N-vinyl-4-ethylpyrrolidone,N-vinyl-4-methylpyrrolidone, N-vinyl-4-methyl-5-ethylpyrrolidone,N-vinyl-4-methyl-5-propylpyrrolidone,N-vinyl-5-methyl-5-ethylpyrrolidone, N-vinyl-5-propylpyrrolidone,N-vinyl-5-butylpyrrolidone, N-vinyl-5-piperidone,N-vinyl-4-methylpiperidone, N-vinyl-4-propylpiperidone,N-vinyl-4-butylpiperidone, N-vinyl-6-butylpiperidone,N-vinylcaprolactam, N-vinyl-4-methylcaprolactam,N-vinyl-6-methylcaprolactam, N-vinyl-6-propylcaprolactam,N-vinyl-7-butylcaprolactam and N-vinylimide. The strong base may beexemplified by t-butyllithium, sodium hydride and n-butyllithium. Thismonomer preparation is carried out in an solvent, examples includen-pentane, n-hexane, n-heptane, cyclohexane, ethylether andtetrahydrofuran. As the source of the protecting group,t-butylchloroformate, isobutylchloroformate, di(t-butyl)dicarbonate,methanesulfonylchloride, methanesulfonic anhydride, tetrahydropyran,2-chlorotetrahydrofuran, trimethylsilylchloride,4-methoxybenzylchloride, 4-nitrobenzylchloride,diethylisopropylsilylchloride and t-dimethylsilylchloride can be used.

The N-vinyllactam derivatives of the present invention are representedby the following general formula (I): ##STR1## wherein, R₁ is hydrogen,an alkyl group containing 1 to 10 carbon atoms, an aryl group containing6 to 12 carbon atoms or a trialkylsilyl group containing 3 to 9 carbonatoms;

R₂ represents -OR', -SO₃ R', -CO₂ R', -PO₃ R', -SO₂ R' or -PO₂ R',wherein R' is an alkyl group containing 1 to 10 carbon atoms, acycloalkyl group, cyclo group containing a heteroatom such as N, O, Pand S, or an aryl group containing 6 to 12 carbon atoms;

R₃ is hydrogen, an alkyl group containing 1 to 10 carbon atoms, an arylgroup containing 6 to 12 carbon atoms, a trialkylsilyl group containing3 to 9 carbon atoms or the same with R₂ ;

R₄ and R₅ is -OH, -OR, wherein R is an alkyl group containing 1 to 10carbon atoms or an aryl group containing 6 to 12 carbon atoms, or thesame with R₁ ; and

m is an integer of 0 to 10.

By the method of the present invention, various monomers can besynthesized, including 3-(t-butoxycarbonyl)-1-vinyl-2-pyrrolidinone,3-(t-butoxycarbonyl)-1-vinyl-4-butyl-2-pyrrolidinone,3-(t-butoxycarbonyl)-1-vinyl-4-propyl-2-pyrrolidinone,3-(tetrahydropyranyloxycarbonyl)-1-vinyl-2-pyrrolidinone,3-(tetrahydropyranyloxycarbonyl)-1-vinyl-5-ethyl-2-pyrrolidinone,3-(t-butoxycarbonyl)-1-vinyl-4-methyl-2-piperidone,3-(t-butoxycarbonyl)-1-vinyl-4-propyl-2-piperidone,3-(t-butoxycarbonyl)-1-vinyl-2-caprolactam,3-(t-butoxycarbonyl)-1-vinyl-4-butyl-2-caprolactam,3-(t-butoxycarbonyl)-1-vinyl-6-methyl-2-caprolactam,3-(tetrahydropyranyloxycarbonyl)-1-vinyl-2-caprolactam,3-(tetrahydropyranyloxycarbonyl)-1-vinyl-5-butyl-2-caprolactam,3-(tetrahydropyranyloxycarbonyl)-1-vinyl-6-propyl-2-caprolactam,3-(tetrahydrofuranyloxycarbonyl)-1-vinyl-2-pyrrolidinone,3-(tetrahydrofuranyloxycarbonyl)-1-vinyl-4-butyl-2-pyrrolidinone,3-(tetrahydrofuranyloxycarbonyl)-1-vinyl-2-caprolactam and3-(tetrahydropyranyloxycarbonyl)-1-vinyl-6-butyl-2-caprolactam.

The synthesized monomers may be easily polymerized in ordinary radicalpolymerization techniques using radical polymerization initiators. Byusing the above-mentioned various monomers, homopolymers from theabove-mentioned monomers and copolymers from the combinations which havean appropriate molar ratio in monomers, can be prepared. For copolymer,other monomers, such as 4-(t-butoxycarbonyloxy) -1-vinylcyclohexane,3,5-(di-t-butoxycarbonyloxy)-1-vinylcyclohexane,4-(tetrahydropyranyloxy)-1-vinylcyclohexane,4- (tetrahydrofuranyloxy) -1-vinylcyclohexane,3,5-(ditetrahydropyranyloxy)-1-vinylcyclohexane,3,5-(ditetrahydrofuranyloxy)-1-vinylcyclohexane,t-butoxycarbonyloxystyrene, styrene and tetrahydropyranyloxystyrene, maybe used.

These are polymerized in bulk polymerization or in a solutionpolymerization. For the solvent for polymerization, cyclohexanone,methylethylketone, benzene, toluene, dioxane, dimethylformamide alone orthe combinations thereof may be used. Usually, the polymerization iscarried out in the presence of a polymerization initiator, such asbenzoylperoxide, 2,2'-azobisisobutyronitrile (AIBN), acetyl peroxide,lauryl peroxide, or t-butylperacetate.

In accordance with the present invention, polymers are provided andrepresented by the following general formulas (II) and (III): ##STR2##wherein, R₁ is hydrogen, an alkyl group containing 1 to 10 carbon atoms,an aryl group containing 6 to 12 carbon atoms or a trialkylsilyl groupcontaining 3 to 9 carbon atoms;

R₂ represents -OR', -SO₃ R', -CO₂ R', -PO₃ R', -SO₂ R' or PO₂ R',wherein R' is an alkyl group containing 1 to 10 carbon atoms, cycloalkylgroup, a cyclo group containing a heteroatom such as N, O, P and S, oran aryl group containing 6 to 12 carbon atoms;

R₃ is hydrogen, an alkyl group containing 1 to 10 carbon atoms, an arylgroup containing 6 to 12 carbon atoms, a trialkylsilyl group containing3 to 9 carbon atoms or the same with R₂ ;

R₄ and R₅ is -OH, -OR, wherein R is an alkyl group containing 1 to 10carbon atoms or an aryl group containing 6 to 12 carbon atoms, or thesame with R₁ ;

R' is an aryl group containing 6 to 20 carbon atoms or represents anacrylate group -COOR'" wherein R'" is an alkyl group containing 1 to 10carbon atoms or an aryl group containing 6 to 12 carbon atoms;

m is an integer of 0 to 10;

n is an integer of 10 to 10,000;

k is mole fraction ranging from 0.5 to 0.95; and

l is mole fraction ranging from 0.05 to 0.5.

As seen in the general formulas, the polymers (II) are homopolymersresulting from one species of the aforementioned monomers or copolymerspolymerizing the mixture of at least two kinds of N-vinyllactammonomers. The polymers (III) are copolymers from N-vinyllactamderivatives and styrene derivatives or vinylacrylate derivatives.

Among the prepared polymers,poly-3-(t-butoxycarbonyl)-1-vinyl-2-pyrrolidone (hereinafter referred toas "P(BCVP)") was found to be highly transparent as proven in theexperiment in which a film 1 μm thick showed an optical absorbance of0.05 or lower at deep uv range (200 to 300 nm). Thermal gravity analysis(hereinafter referred to as "TGA") showed that P(BCVP) was stable at upto 210° C. At higher than 210° C., rapid deprotection oft-butoxycarbonyl group occurs, producing 2-methylpropene and CO₂. In thepresence of acid, the deprotection progresses in two steps. First, thet-butyl group starts to secede from the backbone of the polymer at lowtemperature, e.g. 60° C. and completely breaks away at 100° C.Thereafter, CO₂ is generated at 150° C. This fact informs us thatP(BCVP) is far superior in thermal property by virtue of its highthermal decomposition temperature and is readily deprotected at lowtemperatures in the presence of acid. Differential scanning calorimetry(hereinafter referred to as "DSC") shows that the glass transitiontemperature of P(BCVP) ranges from 145° C. to 155° C. depending on themolecular weight thereof.

All of the polymers of N-vinyllactam derivatives, which are protected atthe 3-position, show excellent film formability. Particularly, P(BCVP)and poly-3-(t-butoxycarbonyl)-1-vinyl-2-caprolactam (hereinafterreferred to as "P(BCVC)"), which are both well dissolved in an organicsolvent, such as dioxane, chloroform, tetrahydrofuran, cyclohexanone,2-ethoxyethylacetate, acetone or methylethylketone. In contrast, thedeprotected polymers are well dissolved in an alkali aqueous solution,such as sodium hydroxide or ammonium gaits, but not in most of theorganic solvents. This selective development before and after thedeprotection of the t-butyl group endows the polymers with superiorpicture formability. In the case of P(BCVP), development can beaccomplished even with only pure water. For other polymers includingP(BCVC), a picture with high resolution can be obtained by developingthe picture in a weak alkali aqueous solution. Of the polymers of thevinyllactam derivatives protected at 3-position, P(BCVP) and P(BCVC)were both found to be of high sensitivity, e.g. 1 mJ/cm², and show highcontrast.

The solubilities of the representative polymers, P(BCVP) and P(BCVC), invarious solvents are changed with the deprotection. A summary is shownin Table 1 below.

In the presence of acid, the deprotection of the t-butyl group wasobserved at 100° C. or lower in the films of such polymers. Ordinaryexperiments for fine picture formation confirmed that the polymers ofthe present invention could be applied for high sensitive chemicalamplification resist. The thermal decomposition behavior analysis of thepolymers was carried out in nitrogen atmosphere at a temperatureelevation of 10° C./min by means of DSC, commercially available fromDuPont company, identified as MODEL 2100, and of TGA.

                  TABLE 1    ______________________________________    Solubility of P (BCVP) and P (BCVC) according to Deprotection    Solvents   P (BCVP) P (BCVC) P (VPCA)*                                         P (VCCA)*    ______________________________________    Acetone    ++       ++       -       -    Dioxane    ++       ++       +       +    Chloroform ++       ++       -       -    Hexane     -        -        -       -    Tetrahydrofuran               ++       ++       +       +    Anisole    +        +        -       -    Cyclohexanone               ++       ++       +       +    2-Ethoxyethyl-               ++       ++       -       -    acetate    N,N-Dimethylform-               ++       ++       +       +    amide    Methylethylketone               ++       ++       +       +    3.0 wt %   +        -        ++      ++    NaOH sol'n    2.38 wt %  +        -        ++      ++    TMAH sol'n    pure Water -        -        ++      ++    Methanol   +        +        +       +    Isopropanol               +        +        +       +    pure Water/MeOH               +        ++       +       +    (1/1)    ______________________________________     ++well dissolved, + a little dissolved,  not dissolved     P (VPCA): poly(1vinyl-2-pyrrolidone-3-carboxylic acid     P (VCCA): poly(1vinyl-2-caprolactam-3-carboxylic acid

A better understanding of the present invention may be obtained in lightof following examples which are set forth to illustrate, but are not tobe construed to limit, the present invention.

EXAMPLE I Synthesis of 3-(t-Butoxycarbonyl)-1-vinyl-2-pyrrolidinone

To a solution of diisopropylamine 14 ml (100 mmol) in tetrahydrofuran 40ml free of moisture, 40 ml (100 mmol) of 2.5 M n-butyllithium was added,and the resulting solution was stirred at -78° C. for 30 min and allowedto react until the temperature was elevated up to room temperature.After being frozen down to -78° C., 11.1 g (100 mmol) ofN-vinylpyrrolidinone was added to the solution and subjected toreaction, at the same temperature for 30 min. Thereafter, 24 g (110mmol) of di(t-butyl)dicarbonate was added dropwise, followed by thereaction at -78° C. for 2 hours. This reaction was diluted withdiethylether and washed many times with pure water. The organic solventof the organic phase was, distilled and the residue was subjected tosilica gel column chromatography, to obtain 15 g of pure3-(t-butoxycarbonyl)-1-vinyl-2-pyrrolidinone (hereinafter referred to as"BCVP"). Its chemical structure was determined by IR spectra and NMR.

EXAMPLE II Synthesis of 3-(t-Butoxycarbonyl)-1-vinyl-2-caprolactam

17.2 g of pure 3-(t-butoxycarbonyl)-1-vinyl-2-caprolactam (hereinafterreferred to as "BCVC") was synthesized in a similar manner to that ofExample I, except for using 13.9 g (100 mmol) of N-vinylcaprolactaminstead of N-vinylpyrrolidinone. IR spectra and NMR analysis were takento determine the chemical structure of BCVC synthesized.

EXAMPLE III Synthesis of3-(Tetrahydropyranyloxycarbonyl)-1-vinyl-2-pyrrolidinone

10.6 g (0.05 mol) of the BCVP synthesized in Example I was dissolved in50 ml of tetrahydrofuran free of moisture. To this solution, 4.3 g (0.05mol) of tetrahydropyran and 0.3 g of p-toluene sulfonic acid was added,and allowed to react at 0° C. for 4 hours. The reaction was diluted withdiethylether and washed several times with pure water. The organicsolvent of the organic phase was distilled and the residue was subjectedto silica gel column chromatography, to obtain 9.8 g of pure3-(tetrahydropyranyloxycarbonyl)-1-vinyl-2-pyrrolidinone (hereinafterreferred to as "TPVP"). The chemical structure of the resulting TPVP wasdetermined by IR spectra and NMR.

EXAMPLE IV Synthesis of3-(Tetrahydrofuranyloxycarbonyl)-1-vinyl-2-pyrrolidinone

8.9 g of N-vinyl-2-pyrrolidinone-3-sodium carbonate was dissolved in 50ml of tetrahydrofuran free of moisture. To this solution, 7 ml oftriethylamine and 5.3 g of 2-chlorotetrahydrofuran were added andallowed to react at room temperature for 1 hours. This reaction wasdiluted with diethylether and washed several times with pure water. Theorganic solvent of the organic phase was distilled and the residue wassubjected to silica gel column chromatography, to obtain 9.3 g of pure3-(tetrahydrofuranyloxycarbonyl)-1-vinyl-2-pyrrolidinone (hereinafterreferred to as "TFVP"). Its chemical structure was determined by IRspectra and NMR.

EXAMPLE V Synthesis of3-(Tetrahydropyranyloxycarbonyl)-1-vinyl-2-caprolactam

10.7 g of pure 3-(tetrahydropyranyloxycarbonyl)-1-vinyl-2-caprolactam(hereinafter referred to as "TPVC") was synthesized in a similar mannerto that of Example III, except that 6.7 g of N-vinylcaprolactam was usedinstead of BCVP.

IR spectra and NMR analysis were taken to determine the chemicalstructure of TVPC synthesized.

EXAMPLE VI Synthesis of3-(Tetrahydrofuranyloxycarbonyl)-1vinyl-2-caprolactam

10.8 g of pure 3-(tetrahydrofuranyloxycarbonyl)-1vinyl-2-caprolactam(hereinafter referred to as "TFVC") was synthesized in a similar mannerto that of Example IV, except that 10.3 g ofN-vinyl-2-caprolactam-3-sodiumcarbonate was used instead ofN-vinyl-2-pyrrolidinone-3-sodium carbonate. IR spectra and NMR analysiswere taken to determine the chemical structure of TFVC synthesized.

EXAMPLE VII Synthesis of BCVP Polymer

2.1 g of BCVP monomer synthesized in Example I was dissolved in a pureor mixed solvent and placed in a polymerization glass ample. Thereactant was polymerized at 70° C. for 6 hours under vacuum in thepresence of AIBN, a polymerization initiator. The reaction product wasprecipitated in petroleum ether and the precipitate was dried to give1.8 g of polymer, P (BCVP): Conversion yield 80%. Its inherent viscositywas observed to vary with the solvents which were used, but determinedin the state of cyclohexanone solution of 0.5 g/dl at 25° C. by use of aglass viscosity tube. The results are shown in Table 2 below.

                  TABLE 2    ______________________________________    Physical Properties of P (BCVP) in Various Solvents                                Con-    Inherent           AIBN.sup.b                   M/S.sup.c                           Time version Viscosity                                               Tg.sup.d    Solvent.sup.a           (mol %) (g/ml)  (hr) Yieid (%)                                        (dL/g) (° C.)    ______________________________________    A      1       1       10   89      <0.10  --    B      1       1       5    89      0.12   --    C      1       1       10   91      0.18   143    D      0.5     1       5    90      0.20   151    E      0.5     1       6    91      0.30   152    F      0.5     1       7    90      0.77   155    ______________________________________     .sup.a A methyethylketone, B cyclohexanone, C dioxane/cyclohexanone (3/1     volume ratio), D dioxane/cyclohexanone (5/1 volume ratio), E     dioxane/cyclohexanone (10/1 volume ratio), F dioxane     .sup.b mol % based on the monomer     .sup.c ratio of solvent volume to the total weight of monomer     .sup.d glass transition temperature

EXAMPLES VIII THROUGH XII Synthesis of BCVC, TPVP, TFVP, TPVC and TFVCpolymers

Polymers, P(BCVC), P(TPVP), P(TFVP), P(TPVC) and P(TFVC) were preparedwith the same procedure that was used in Example VII, using monomers,BCVC, TPVP, TFVP, TPVC and TFVC, synthesized in Examples II through VI,respectively.

EXAMPLE XIII

Preparation of Resist Sol'n and Formation of Positive Fine Picture (I)

10 to 30% by weight of P(BCVP) was dissolved in cyclohexanone. In thissolution, an onium salt or organic sulfonic acid, acting as a photoacidgenerator, was added at an amount of 5 to 30% by weight based on theweight of the resist polymer. Filtration with a ultrafine filter gave achemical amplification resist solution. Subsequently, it was spin-coatedon a silicon wafer, to form a thin film with a thickness of about 1.0μm. This wafer was pre-baked for 1 to 5 minutes in an oven or hot plateheated to 120° C., exposed to the light radiated from a deep uv stepperor excimer laser stepper, subjected to post exposure-baking (PEB) for 1to 5 minutes in an oven or hot plate heated from to 120 to 140° C. andimmersed in pure water for 90 seconds for development. As a result, apositive resist picture of submicrons was obtained.

EXAMPLE XIV Preparation of Resist Sol'n and Formation of Positive FinePicture (II)

Using P(BCVC), the procedure of Example XIII was repeated to obtain aresist solution. Immersion in 0.8 wt % TMAH aqueous solution for 90seconds gave a positive resist picture of submicrons.

As described and proven hereinbefore, the novel N-vinyllactamderivatives of the present invention are materials for homopolymerscopolymers for use as chemical amplification resist suitable for deepuv. In addition, the photoresist made of the polymers according to thepresent invention is of high sensitivity so that pictures can be formedwith high resolution. Therefore, the radiation-sensitive polymers can beapplied for highly integrated semiconductor devices and electron devicelithography. Consequently, ultrafine circuits can be formed and anexceptional improvement in pattern formation can be attained by usingthe photoresist prepared according to the present invention.

The present invention has been described in an illustrative manner, andit is to be understood that the terminology being used is intended to bein the nature of description rather than of limitation.

Many modifications and variations of the present invention are possiblein light of the above teachings. Therefore, it is to be understood thatwithin the scope of the appended claims, the invention may be practicedin ways other than those specifically described.

What is claimed is:
 1. Homopolymers or copolymers of N-vinyllactamderivatives, represented by the following general formula (II): ##STR3##wherein. R₁ is hydrogen, an alkyl group containing 1 to 10 carbon atoms,an aryl group containing 6 to 12 carbon atoms or a trialkylsilyl groupcontaining 3 to 9 carbon atoms;R₂ represents -OR', -SO₃ R', -CO₂ R',-PO₃ R', -SO₂ R' or PO₂ R' wherein R' is an alkyl group containing 1 to10 carbon atoms, cycloalkyl group, a cyclo group containing a heteroatomsuch as N, O, P and S, or an aryl group containing 6 to 12 carbon atoms;R₃ is hydrogen, an alkyl group containing 1 to 10 carbon atoms, an arylgroup containing 6 to 12 carbon atoms, a trialkylsilyl group containing3 to 9 carbon atoms or the same with R₂ ; R₄ and R₅ is -OH, -OR, whereinR is an alkyl group containing 1 to 10 carbon atoms or an aryl groupcontaining 6 to 12 carbon atoms, or R is the same with R₁ ; m is aninteger of 1 to 3; and n is an integer of 10 to 10,000.
 2. A chemicalamplification photoresist comprising the polymers of claim
 1. 3.Homopolymers or copolymers prepared from N-vinyllactam derivatives andstyrene derivatives or vinylacrylate derivatives, represented by thefollowing general formula (III): ##STR4## wherein, R₁ is hydrogen, analkyl group containing 1 to 10 carbon atoms, an aryl group containing 6to 12 carbon atoms or a trialkylsilyl group containing 3 to 9 carbonatoms;R₂ represents -OR', -SO₃ R', -CO₂ R', -PO₃ R', -SO₂ R' or PO₂ R',wherein R' is an alkyl group containing 1 to 10 carbon atoms, cycloalkylgroup, a cyclo group heteroatom such as N, O, P and S, or an aryl groupcontaining 6 to 12 carbon atoms; R₃ is hydrogen, an alkyl groupcontaining 1 to 10 carbon atoms, an aryl group containing 6 to 12 carbonatoms, a trialkylsilyl group containing 3 to 9 carbon atoms or the samewith R₂ ; R₄ and R₅ is -OH, -OR, wherein R is an alkyl group containing1 to 10 carbon atoms or an aryl group containing 6 to 12 carbon atoms,or the same with R₁ ; R" is an aryl group containing 6 to 20 carbonatoms or represents an acrylate group -COOR'" wherein R'" is an alkylgroup containing 1 to 10 carbon atoms or an aryl group containing 6 to12 carbon atoms; m is an integer of 1 to 3; n is an integer of 10 to10,000; k is a mole fraction ranging from 0.5 to 0.95; and l is a molefraction ranging from 0.05 to 0.5.
 4. A chemical amplificationphotoresist comprising the polymers of claim 3.